2-Iodo-N-isopropyl-5-methoxybenzamide as a highly reactive and environmentally benign catalyst for alcohol oxidation

• Takayuki Yakura,
• Tomoya Fujiwara,
• Akihiro Yamada and
• Hisanori Nambu

Beilstein J. Org. Chem. 2018, 14, 971–978, doi:10.3762/bjoc.14.82

• -OMe < 5-OAc < 5-Cl < H, 4-OMe < 5-Me < 5-OMe. The oxidation of various benzylic and aliphatic alcohols using a catalytic amount of the most reactive 5-methoxy derivative successfully resulted in moderate to excellent yields of the corresponding carbonyl compounds. The high reactivity of the 5-methoxy

• . Zhdankin and colleagues reported the oxidation of alcohols to their corresponding carbonyl compounds using several 2-iodoxybenzamides [23]. Therefore, we tried to confirm the formation of 2-iodoxybenzamide 29 from 2-iodobenzamide 17 in an oxidation reaction (Scheme 1). Iodoarene 17 was treated with 2.5

• excellent yields of the corresponding carbonyl compounds 15 and 26. The higher reactivity of 17 at room temperature results from the rapid oxidation of trivalent iodine compound 27 to the pentavalent compound 29. 5-Methoxy-2-iodobenzamide 17 promises to be an efficient and environmentally benign catalyst

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• iodine reagents using a lactate motif has been employed for several types of oxidation reaction since we first reported this procedure [18]. Enantioselective oxidative transformations include the dearomatization of phenols [19][20][21][22][23][24], α-functionalization of carbonyl compounds [25][26][27

Addition of dithi(ol)anylium tetrafluoroborates to α,β-unsaturated ketones

• Yu-Chieh Huang,
• An Nguyen,
• Simone Gräßle,
• Sylvia Vanderheiden,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2018, 14, 515–522, doi:10.3762/bjoc.14.37

• -withdrawing substituents in α-position [9][26]. Our recent approach to the synthesis of α-arylazo-carbonyl compounds showed that easily available dithi(ol)anylium tetrafluoroborates [27][28] (following shortened to TFBs) serve as stable precursors for ketene dithioacetals [29]. In accordance with previous

• examples for additions of activated (EWG-substituted) ketene 1,3-dithioacetals to α,β-unsaturated carbonyl compounds are literature known [31][32] but concepts for a versatile (metal-free) application of this reaction to starting materials lacking the EWG in α-position are still missing. Results and

• HBF4. The scope of the dithi(ol)anylium TFB addition to α,β-unsaturated carbonyl compounds In order to determine the scope of the herein presented reaction, we used compound 1c for further conversions indicating the possible challenges and aims of forthcoming projects (Scheme 5). With two selected

Continuous multistep synthesis of 2-(azidomethyl)oxazoles

• Thaís A. Rossa,
• Nícolas S. Suveges,
• Marcus M. Sá,
• David Cantillo and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2018, 14, 506–514, doi:10.3762/bjoc.14.36

• ]. An alternative approach consists of the ring expansion of azirines, which can be prepared from vinyl azides 1, by the reaction with carbonyl compounds. Substituted 2-acylazirines rearrange to oxazoles in the presence of bases [24][25][26]. In addition the light-mediated synthesis of oxazoles from

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• iodomethane in acetone in the presence of potassium carbonate to give methyl thioether 188 which provided hydrazinopyrazolo[3,4-d]pyrimidines 189 on treatment with an excess of hydrazine hydrate in ethanol. The hydrazine derivative 189 thus obtained was made to react with several carbonyl compounds like

Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides

• Masanori Inaba,
• Tatsuya Sakai,
• Shun Shinada,
• Tsuyuka Sugiishi,
• Yuta Nishina,
• Norio Shibata and
• Hideki Amii

Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12

• ). Previously, Shibata et al. reported a cinchona alkaloid/Me4NF-catalyzed nucleophilic enantioselective trifluoromethylation of carbonyl compounds [33][34][35]. Initially, we tried to conduct the reaction of 2-cyanobenzaldehyde (2) with CF3–SiMe3 in the presence of cinchona alkaloids 9/TMAF combination (Table

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• )–H with a electrophilic trifluoromethylation reagent (Togni’s reagent): N,N-Dialkylhydrazones were widely used in organic chemistry, including using as synthetic equivalents of carbonyl compounds, as precursors to substituted hydrazines or primary amines. In 2013, Baudoin and co-workers [53] firstly

Conformational preferences of α-fluoroketones may influence their reactivity

• Graham Pattison

Beilstein J. Org. Chem. 2017, 13, 2915–2921, doi:10.3762/bjoc.13.284

• electrophiles available to synthetic chemists for SN2 substitution [5]. The orbital overlap in α-halogenated ketones also provides activation to the carbonyl group, making it more reactive towards nucleophilic addition than non-halogenated carbonyl compounds [6]. However, relatively little work has been

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• the α-CF3 carbonyl compound 4 (Scheme 3). Unactivated olefins are widely available substrates prone to be transformed into α-trifluoromethyl carbonyl compounds under oxidative trifluoromethylation as first reported by Maiti and co-workers in 2013. The reaction is operationally simple, conducted under

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• several interesting synthetic applications, although they have only relatively recently become known. Deprotonated 2-aminovinylphosphonium salts can be employed in Wittig reactions with carbonyl compounds. Thus the intramolecular Wittig reaction of 2-(2-acylphenylamino)vinylphosphonium salts 56 in the

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• carbonyl compounds, activated multiple bonds, or other nucleophiles to furnish heterocyclic cores [22][23][24][25][26][27][28][29][30][31][32]. Similar intramolecular transformations of intermediate ylides with several nucleophilic reaction centers in the initial substrate, are also possible. The known

• the study (Figure 1). Dirhodium carboxylates [Rh2(OAc)4, Rh2(Oct)4 and Rh2(Piv)4] which were found to be the most effective catalysts in reactions of diazo carbonyl compounds with different substrates [46][47], were employed in this research. At first, we studied reactions of thioamides 1 with

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

• Dmitry Yu. Vandyshev,
• Khidmet S. Shikhaliev,
• Andrey Yu. Potapov,
• Michael Yu. Krysin,
• Fedor I. Zubkov and
• Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

• itaconimides, four primary adducts 5–8 could result (Scheme 5) based on the well-known fact that the heterocyclization reactions of α,β-unsaturated carbonyl compounds with dinucleophilic reagents typically begin with addition like Michael’s reaction, including heterocyclic dinucleophiles [39][40][41][42

• equivalent of C1-electrophile: R2COOH/T3P® [15], BrCN (R2 = NH2) [16], ArNCS/DCC (R2 = NHAr) [20]. Heterocyclization of 1-aminoimidazoles with 1,3-dicarbonyl or α,β-unsaturated carbonyl compounds (route B). Conditions: i) R1 = NH2, NHAlk, R2 = Ph, R3,4 = Alk, Ar, solvent-free [24], AcOH [25][26], R3 = Ph, R4

Is the tungsten(IV) complex (NEt₄)₂[WO(mnt)₂] a functional analogue of acetylene hydratase?

• Matthias Schreyer and
• Lukas Hintermann

Beilstein J. Org. Chem. 2017, 13, 2332–2339, doi:10.3762/bjoc.13.230

• generation of 10, and the source and purification method for substrate 2 were not indicated [13]. Derivatization to 2,4-dinitrophenylhydrazones is a well-established identification method for carbonyl compounds that recommends itself for small amounts of volatile products [38][39]. However, aldehyde

• through an acidic solution of DNPH to absorb volatile carbonyl compounds. Emphasis was placed both on unequivocal and direct analysis of acetaldehyde (3) in the reaction solution, and on identification of all major species in the reaction solution or the DNPH solution. For this purpose, 1H and 13C NMR

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

• Raju Cheerlavancha,
• Ahmed Ahmed,
• Yun Cheuk Leung,
• Aggie Lawer,
• Qing-Quan Liu,
• Marina Cagnes,
• Hee-Chan Jang,
• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

• β-fluorinated carbonyl compounds besides 9. Thus, β-fluoroaldehyde 17 which was synthesized by an independent method (see Supporting Information File 1) was treated with NFSI and catalyst 10 according to Jørgensen’s fluorination protocol [20] (Table 1, entry 1). However, this resulted in a complex

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

• Andrea Porcheddu,
• Evelina Colacino,
• Giancarlo Cravotto,
• Francesco Delogu and
• Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

• primary and secondary alcohols to the corresponding aldehydes and ketones by mechanical processing under air. Ball milling was shown to promote the quantitative conversion of a broad set of alcohols into carbonyl compounds with no trace of an over-oxidation to carboxylic acids. The mechanochemical

• observed. Conclusion We have developed a TEMPO-based oxidative procedure for the air oxidation of primary and secondary benzyl alcohols to the corresponding aldehydes and ketones under ball milling conditions. A library of common alcohols was efficiently converted into carbonyl compounds with no trace of

• -based oxidations. Studies are underway to identify more effective TEMPO-based catalysts that are also capable of promoting the oxidation of non-activated alcohols. Experimental General procedure to prepare carbonyl compounds 2a–v. 2,2,6,6-Tetramethylpiperidine 1-oxyl (TEMPO, 9.4 mg, 0.06 mmol, 3 mol

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• (Scheme 23). α,β-Unsaturated carbonyl compounds could also undergo a trans-bromination reaction efficiently within 40 min. Following to Wang’s report, Stolle and co-workers also reported a similar method of aryl bromination and chlorination using NaBr and NaCl, respectively, in the presence of oxidizing

NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

• Ken Takaki,
• Makoto Hino,
• Akira Ohno,
• Kimihiro Komeyama,
• Hiroto Yoshida and
• Hiroshi Fukuoka

Beilstein J. Org. Chem. 2017, 13, 1816–1822, doi:10.3762/bjoc.13.176

• convert aldehydes to nucleophilic species, which react with activated alkenes to yield hydroacylation products [10][11][12][13][14]. When the carbonyl compounds I other than aldehyde behave similarly, functionalized 1,4-diketones IV would be produced (Scheme 1). Previously, we reported that benzils I (G

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• the hereby accessed products can be of significant interest with respect to biological or medical applications, which is especially the case for α-fluoro targets [64][65]. On the other hand, such α-halo carbonyl compounds may serve as valuable intermediates for further manipulations like, for example

• , enantiospecific nucleophilic displacement reactions [66][67]. α-Fluorinations The stereoselective electrophilic α-fluorination of carbonyl compounds became a thoroughly investigated field over the course of the last 15 years [68][69][70][71][72]. A variety of different catalytic approaches, either relying on the

• that use SelectfluorTM (8) as a simple and highly reactive electrophilic F-transfer reagent. Besides fluoro-cyclizations of olefines [56], also the asymmetric α-fluorination of prochiral carbonyl compounds or analogues like enamides 7 has been carried out with remarkable enantioselectivities by using

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• another convenient method for the reduction of carbonyl compounds, although low selectivities have sometimes been observed and the reaction usually required drastic conditions [9]. Also, the catalytic hydrosilylation of carbonyl moieties has become an important transformation as an alternative reduction

• structure, so this reaction could be considered as a new regiospecific method of a desulfinylation. In order to examine the scope of observed desulfinylation different carbonyl compounds with sulfinyl substituents were synthetized and subjected to the reaction with phenylsilane. Reactions of α

Development of a method for the synthesis of 2,4,5-trisubstituted oxazoles composed of carboxylic acid, amino acid, and boronic acid

• Kohei Yamada,
• Naoto Kamimura and
• Munetaka Kunishima

Beilstein J. Org. Chem. 2017, 13, 1478–1485, doi:10.3762/bjoc.13.146

• materials, such as α-haloketones and primary amides [8], alkynes and nitriles [9], amines and α,β-unsaturated carbonyl compounds [10], etc. [11] have been reported. However, these reactions are often conducted under harsh reaction conditions and multistep syntheses of the starting materials are needed. ii

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• aldehydes or ketones (mainly formaldehyde) with ammonia or aliphatic amines and CH-acidic carbonyl compounds, known as the Mannich reaction, plays an important role in organic synthesis, despite some limitations of this reaction. α-Amidoalkylation reactions are considered an important extension of the

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• (Scheme 1) [20]. A hydroxy group neighbouring an alkynyl substituent, under treatment with acids, normally leads to Rupe and Meyer–Schuster rearrangements, forming unsaturated carbonyl compounds. This was indeed observed in camphor-derived bicyclic alcohols containing a single ethinyl group [21][22

α-Acetoxyarone synthesis via iodine-catalyzed and tert-butyl hydroperoxide-mediateded self-intermolecular oxidative coupling of aryl ketones

• Liquan Tan,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2017, 13, 1079–1084, doi:10.3762/bjoc.13.107

• products and pharmaceuticals, and α-acetoxyaryl ketones are widely used as synthetic intermediates [1][2][3][4][5]. Traditional methods for the preparation of α-acyloxy ketones focus on the substitution reactions of α-halo carbonyl compounds with alkaline carboxylates or carboxylic acids [6][7], and

• transition-metal-catalyzed direct oxidative coupling reactions of carbonyl compounds with carboxylic acids (or their surrogates) [8][9]. Recently, robust approaches using organohypervalent iodine reagents and peroxide-mediated oxidative coupling have been developed [10][11]. Although impressive progress has

Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents

• Josef Jansa,
• Ramona Schmidt,
• Ashenafi Damtew Mamuye,
• Laura Castoldi,
• Alexander Roller,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2017, 13, 895–902, doi:10.3762/bjoc.13.90

• most common strategies employ reactions of 1,3-dicarbonyl compounds or α,β-unsaturated carbonyl compounds with substituted hydrazines [4][6][19]. To overcome the drawbacks of this method, namely insufficient regioselectivity [20], other accesses such as, for instance, regioselective metalations of N

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• carbonyl compounds could successfully generate an enamine or an enolate, and these species react as dipolarophiles with organic azides in organocatalyzed 1,3-dipolar cycloadditions. Our research group has demonstrated β-enamine–azide cycloaddition reactions for the synthesis of selenium-functionalized